JP2002252457A - Multilayer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem raised by a multilayer wiring board in which an insulating layer composed of a plurality of insulating film layers is formed on a substrate that the insulating film layers swell out when coupling agent layers evaporate and conductor layers formed in this wires are disconnected. SOLUTION: This multilayer wiring board is constituted by laminating the insulating film layers 4 composed of an organic resin and carrying the conductor layers 3 on their upper surfaces upon another, respectively, by sticking the layers 4 to each other by insulating adhesive layer 5. Each conductor layer 3 is composed of a base conductor layer 8 and a main conductor layer 7 carrying a coupling agent layer 6 having a thickness corresponding to that of five molecular layers or thinner on its upper surface. Consequently, the widths of the conductor layers 3 can be reduced and, at the same time, the evaporation of the coupling agent layers 6 between the insulating film layers 4 can be eliminated. Therefore, the insulating film layers 4 do not swell out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board, and more particularly to a multilayer wiring board used for a hybrid integrated circuit device, a semiconductor element housing package for housing a semiconductor element, and the like.

[0002]

2. Description of the Related Art Conventionally, as a multilayer wiring board used for a hybrid integrated circuit device, a package for housing a semiconductor element, and the like,
For the purpose of forming wiring conductors at a high density, a multilayer wiring board in which a multilayer wiring portion composed of a thin insulating layer and a conductor layer is formed on a substrate has been employed.

In such a multilayer wiring board, an insulating layer of a thin film made of polyimide resin or the like formed by a spin coating method or the like, a main conductor layer of copper or the like, It consists of upper and lower barrier conductor layers such as chromium and nickel, and alternately laminates the main conductor layer of a multilayer film formed by adopting thin film forming technology such as plating method and vapor deposition method and photolithography technology. It has the structure made to be.

However, when an insulating layer made of a polyimide resin is formed by spin coating, a polyimide resin precursor is applied in a number of steps to form an insulating layer having a desired thickness. Since a curing step for converting the body into a polyimide is required, there has been a problem that the manufacturing process becomes longer.

Further, in order to prevent the copper contained in the main conductor layer from being corroded by components contained in the precursor of the polyimide resin, the main conductor layer is exposed to a high temperature of 300 ° C. or more for a long time in the curing step of the polyimide resin. In order to prevent the copper of the layer from being oxidized, the conductor layer needs to have a main conductor layer such as copper and a barrier conductor layer such as chromium, nickel and titanium above and below the main conductor layer. There is a problem that the manufacturing process for processing becomes long.

Therefore, a multilayer wiring board is employed in which a plurality of insulating film layers made of a polyimide resin or the like and having a conductor layer formed on the upper surface are adhered to each other with an insulating adhesive layer made of a bismaleimide-based resin or the like and laminated in multiple layers. Is coming.

In order to form such a multilayer wiring board, first, an insulating film is coated with an insulating adhesive by a doctor blade method or the like and dried, and a conductive layer is formed on the upper surface by plating or copper foil transfer. This is performed by stacking the insulating film layers such that the insulating adhesive layer is disposed on the upper surface of the formed substrate or the lower insulating film layer, and applying heat and pressure using a heating press device to bond the insulating film layers.

According to this multilayer wiring board, the curing step for converting the precursor of the polyimide resin into a polyimide can be reduced, and a multilayer wiring board having a short manufacturing process can be obtained because the barrier conductor layer of the conductor layer becomes unnecessary. .

However, in this multilayer wiring board, the upper and lower surfaces of the conductor layer and the insulating film layer are chemically roughened with a processing liquid in order to secure the adhesive strength between the conductor layer and the insulating film layer. For this reason, the upper and lower surfaces of the conductor layer and the insulating film layer become rough surfaces having irregularities, and in the conductor layer where fine wires are to be formed, over-etching may occur in the process of forming the irregularities and disappear, and the conductor layer may be lost. There is a problem that thinning cannot be performed.

Therefore, a multilayer wiring board is adopted in which a plurality of insulating film layers made of an organic resin and having a conductor layer formed on the upper surface are laminated in multiple layers by bonding with an insulating adhesive layer via a coupling agent layer. Have been.

According to this multilayer wiring board, the adhesion strength between the conductor layer and the insulating film layer can be obtained without roughening the upper surface of the conductor layer to make the upper surface of the conductor layer uneven, so that the wiring in the conductor layer can be thinned. .

[0012]

However, in a multilayer wiring board using a coupling agent layer, a part of the coupling agent layer is formed between the insulating film layers by heat treatment at the time of forming a conductor layer or mounting chip components. Evaporates, and the insulating film layer swells.

Further, the upper surface of the insulating film layer is made to have a rough surface having irregularities in order to strengthen the adhesive strength with the conductor layer formed on the upper surface. For this reason, there has been a problem that the fine conductor layer may be disconnected due to the unevenness of the upper surface of the insulating film layer, and it cannot be sufficiently responded to the demand for further thinning.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to prevent the insulating film layer from swelling due to heat treatment, to have a strong adhesive strength of the insulating film layer, and to provide a high-density wiring. It is to provide a multilayer wiring board which can be used.

[0015]

According to the present invention, there is provided a multilayer wiring board comprising a plurality of insulating film layers made of an organic resin and having a conductor layer formed on an upper surface thereof, which are bonded to each other with an insulating adhesive layer. A multilayer wiring board having a multi-layer structure, wherein a conductor layer comprises a base conductor layer and a main conductor layer, and a coupling agent layer having a thickness of 5 molecular layers or less is formed on an upper surface of the main conductor layer. It is assumed that.

Further, in the multilayer wiring board of the present invention, in the above structure, the base conductor layer is made of chromium or an alloy mainly containing chromium, and the main conductor layer is made of copper or an alloy mainly containing copper. The insulating film layer is formed of a polyimide resin, the insulating adhesive layer is formed of a polyimide siloxane resin, and the coupling agent layer is formed of isopropyl tri-N-aminoethylaminoethyl titanate.

According to the multilayer wiring board of the present invention, since the coupling agent layer is formed on the upper surface of the main conductor layer to have a thickness of 5 molecular layers or less, the coupling agent layer has a small disorder in the arrangement of molecules, and the The molecules of the body layer and the coupling agent layer are efficiently bonded to each other to form a uniform and strong layer, and no isolated coupling agent molecules are generated. As a result, the heat resistance of the coupling agent layer is improved, the evaporation of the coupling agent layer in the heating step is eliminated, and the main conductor layer and the insulating adhesive layer are firmly bonded by the coupling agent layer.

Further, since the conductor layer is composed of a base conductor layer and a main conductor layer, the main conductor layer has good electric conductivity as a circuit wiring, and the base conductor layer has an adhesive strength with an insulating film layer. Can be adopted depending on the required function. Therefore, the adhesive strength between the insulating film layer and the main conductor layer can be strengthened, and it is not necessary to roughen the upper surface of the insulating film layer to have irregularities. Will not occur.

Thus, it is possible to obtain a multilayer wiring board which does not cause swelling of the insulating film layer due to the heat treatment, has strong adhesive strength of the insulating film layer, and is capable of high-density wiring.

Further, according to the multilayer wiring board of the present invention,
The base conductor layer is made of chromium or an alloy containing chromium as a main component, the main conductor layer is made of copper or an alloy containing copper as a main component, the insulating film layer is made of a polyimide resin, and the insulating adhesive layer is made of a polyimide siloxane resin. When the ring agent layer is formed of isopropyltri-N-aminoethylaminoethyl titanate, the isopropyltri-N-aminoethylaminoethyl titanate has good wettability with copper / polyimide resin / polyimide siloxane resin and easily bonds firmly, Further, since the heat resistance is high in the molecular structure, the adhesive strength between the respective layers is strengthened, and it is possible to cope with a higher temperature heat treatment. As a result, the heat resistance of the coupling agent layer is improved, the evaporation of the coupling agent layer between the insulating film layers is eliminated even at a higher temperature heat treatment, and the main conductor layer and the insulating adhesive layer are strengthened by the coupling agent layer. Adhered to.

Further, since chromium forms a chemical bond with the polyimide resin, the adhesive strength is strong even if the upper surface of the insulating film layer is smooth. For this reason, unevenness on the upper surface of the insulating film layer becomes unnecessary, and even if a thin conductor layer is formed, disconnection does not occur, and the thin main conductor layer can be more firmly bonded to the insulating film layer.

According to this, it is possible to obtain a multilayer wiring board in which the insulating film layer and the conductor layer do not swell even by heat treatment at a higher temperature, the adhesive strength between the insulating film layer and the conductor layer is further increased, and high-density wiring is possible. Can be.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing an example of an embodiment of a multilayer wiring board according to the present invention, and FIG. 2 is an enlarged sectional view of a main part showing a part of the conductor layer.

In these figures, 1 is a substrate, 2 is a multilayer wiring portion, 3 is a conductor layer, 4 is an insulating film layer, 5 is an insulating adhesive layer, 6 is a coupling agent layer, 7 is a main conductor layer, 8 is a base conductor layer.

The substrate 1 is provided with a multilayer wiring portion 2 in which a plurality of insulating film layers 4 each having a conductor layer 3 formed on the upper surface thereof are adhered to each other with an insulating adhesive layer 5 and laminated in multiple layers. It functions as a support member for supporting the multilayer wiring section 2.

The substrate 1 is made of an oxide ceramic such as an aluminum oxide sintered body or a mullite sintered body, or a non-oxide ceramic such as an aluminum nitride sintered body or a silicon carbide sintered body having an oxide film on its surface. It is formed of an electrically insulating material such as an oxide ceramic, a glass epoxy resin in which a glass fiber base material is impregnated with an epoxy resin, and a glass fiber base material in which a bismaleimide triazine resin is impregnated. .

For example, in the case of being formed of an aluminum oxide-based sintered body, an appropriate organic solvent and a solvent are added to a raw material powder such as alumina, silica, calcia, and magnesia, and the mixture is mixed to form a slurry. A ceramic green sheet (ceramic green sheet) is formed by employing a conventionally known doctor blade method or calender roll method. Thereafter, the ceramic green sheet is subjected to an appropriate punching process to obtain a predetermined shape and a high temperature (approximately). 1600 ° C) or by mixing an appropriate organic solvent / solvent with the raw material powder such as alumina to prepare the raw material powder and forming the raw material powder into a predetermined shape by a press molding machine. It is manufactured by firing a molded body at a high temperature (about 1600 ° C.). In the case of a glass epoxy resin, for example, a substrate made of glass fiber is impregnated with an epoxy resin precursor,
The epoxy resin precursor is manufactured by thermosetting at a predetermined temperature.

The conductor layer 3 of the multilayer wiring portion 2 provided on the upper surface of the substrate 1 functions as a transmission path for transmitting electric signals, and the insulating film layer 4 electrically connects the upper and lower conductor layers 3 to each other. It has a function to insulate it. Further, a through hole processed by a laser or the like is formed in the insulating film layer 4, the insulating adhesive layer 5, and the coupling agent layer 6, and the upper conductor layer 3 is also extended in the through hole. Thereby, a connection path for electrically connecting each of the conductor layers 3 positioned above and below the insulating film layer 4 is formed.

The insulating layer of the multilayer wiring section 2 is composed of an insulating film layer 4 and an insulating adhesive layer 5, and the insulating film layer 4 is made of polyimide resin, epoxy resin, polyphenylene sulfide resin, polyquinoline resin, polyphenylene ether resin, etc. Consists of The insulating adhesive layer 5 is made of a polyamide imide resin, a polyimide siloxane resin, a bismaleimide resin, an epoxy resin, or the like.

For example, when the insulating film layer 4 is a polyimide resin and the insulating adhesive layer 5 is a polyimide siloxane resin, the insulating layer of the multilayer wiring section 2 is formed as follows. First, a polyimide siloxane resin as an insulating adhesive is applied to a polyimide resin as an insulating film having a thickness of about 12.5 to 50 μm by a doctor blade method or the like to a dry thickness of 5 μm.
Prepare a material that has been applied and dried to about 20 μm. Next, the insulating film layer 4 is stacked so that the insulating adhesive layer 5 is arranged between the main conductor layer 7 on which the coupling agent layer 6 is formed and the upper surface of the lower insulating film layer 4. Then, this is heated and pressurized by using a heating press device and bonded.

The main conductor layer 7 disposed on the upper surface of each of the insulating film layers 4 and in the through holes is made of a low-resistance metal material such as copper, gold, silver, aluminum or an alloy containing these as a main component. It is formed by adopting a thin film forming technique such as a deposition method, a vapor deposition method, and a plating method and an etching processing technique. The underlying conductor layer 8 is made of a metal material such as chromium, nickel, molybdenum, titanium, tantalum, tungsten, or an alloy containing these as a main component, and adopts a thin film forming technique such as a sputtering method or a vapor deposition method and an etching technique. Formed by

For example, the main conductor layer 7 and the underlying conductor layer 8
First, copper is applied as a main conductor layer 7 over a wide area, and chromium is applied as a base conductor layer 8 (adhesion metal layer) below the copper layer to form a conductor layer. Next, a photoresist is formed in a desired pattern thereon, and unnecessary portions of the main conductor layer 7 and the underlying conductor layer 8 are removed by etching using the photoresist as a mask, whereby the photoresist is processed into a desired pattern.

The coupling agent layer 6 is provided on the upper surface of the main conductor layer 7.
To form The coupling agent layer 6 strengthens the adhesive strength between the main conductor layer 7 and the insulating adhesive layer 5 and functions as a layer for improving the adhesive strength in the heat treatment.

The coupling agent layer 6 is made of N-β (aminoethyl) γ-aminopropyltrimethoxysilane.
Phenyl-γ-aminopropyltrimethoxysilane ・ γ
-Β (aminoethyl) γ-aminopropyltrimethoxysilane / vinyltriethoxysilane / vinyltris (β
Methoxyethoxy) silane / γ-methacryloxypropyltrimethoxysilane / N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane / γ-chloropropyltrimethoxysilane / γ-aminopropyltriethoxysilane / isopropyltridodecylbenzenesulfonyl Titanate / isopropyl tris (dioctyl pyrophosphate) titanate / dicumylphenyloxyacetate titanate / isopropyltri N-aminoethylaminoethyl titanate / isopropyltrioctanoyl titanate / isopropyl dimethacryl isostearyl titanate / isopropyl isostearyl diacryl titanate / acetoalkoxy It is made of aluminum diisopropylate or the like. The method of forming the coupling agent layer 6 may be a spin coating method, a dipping method, or the like, but it is preferable to form the coupling agent layer 6 by using an LB film method in order to improve the uniformity of the film.

When the coupling agent layer 6 is formed by using the LB film method, for example, the coupling agent is dispersed to a desired thickness on the liquid surface while the surface pressure is kept constant, and the film surface is The coupling agent layer 6 is formed in a uniform thickness over the entire surface of the substrate 1 by vertically immersing the substrate 1 on which the main conductor layer 7 is formed and slowly lifting the substrate 1 as it is.

At this time, when the thickness of the coupling agent layer 6 is 5
When the thickness of the coupling agent layer 6 is larger than the thickness of the molecular layer, the arrangement of the molecules in the coupling agent layer 6 becomes more disordered, the number of molecules of the isolated coupling agent increases, and part of the coupling agent layer 6 between the insulating film layers 4 due to heat treatment. It is preferable that the thickness of the coupling agent layer 6 be equal to or less than the thickness of five molecular layers because the insulating film layer 4 tends to swell due to evaporation.

Incidentally, the size of one molecule of the coupling agent is about 2 nm, which means that the thickness is about 10 nm in the case of a five-molecule layer. Even when the thickness of the coupling agent layer 6 does not become uniform, the occupancy of the portion of the coupling agent layer 6 having a thickness of 1.3.5 molecular layer is particularly 60%. Above is an effect of improving the adhesive strength.

Further, if the coupling agent layer 6 is formed on the upper surface of the insulating film layer 4 other than the portion where the main conductor layer 7 is formed, the lower insulating film layer 4 and the insulating adhesive layer 5 Of the insulating film layer 4 during the heat treatment does not occur. Furthermore, even in an environmental resistance test such as a high temperature / humidity bias test, the occurrence of migration or the like occurring between the conductor layers 3 in the same plane is prevented, and the environmental reliability is improved.

At this time, when the thickness of the coupling agent layer 6 is 5
When the thickness is larger than the molecular layer thickness, the arrangement of the molecules of the coupling agent layer 6 becomes more disordered, the number of molecules of the isolated coupling agent increases, and part of the coupling agent layer between the insulating film layers 4 due to heat treatment. Evaporated insulating film layer 4
It is preferable that the thickness of the coupling agent layer 6 be equal to or less than the thickness of five molecular layers because the swelling tends to occur easily.

The coupling agent layer 6 formed on the insulating film layer 4 may be the same as that formed on the upper surface of the main conductor layer 7, but different types of coupling may be used depending on the combination of materials to be bonded. The agent may be changed.

Further, the combination of the materials of the main conductor layer 7, the base conductor layer 8, the insulating film layer 4, and the insulating adhesive layer 5 may be appropriately selected according to the specifications and characteristics required for the multilayer wiring board. In particular, the main conductor layer 7 is made of copper, the base conductor layer 8 is made of chromium, the insulating film layer 4 is made of polyimide resin, the insulating adhesive layer 5 is made of polyimide siloxane resin, and the coupling agent layer 6 is made of polyimide siloxane resin.
Is formed with isopropyl tri-N-aminoethylaminoethyl titanate, isopropyl tri-N-aminoethylaminoethyl titanate is converted to copper / polyimide resin /
It has good wettability with the polyimide siloxane resin and is easily bonded firmly.Because isopropyl tri-N-aminoethylaminoethyl titanate has high molecular structure and high heat resistance, the adhesive strength between each layer becomes strong and the temperature becomes higher. Can also be applied.

As a result, the insulating film layer 4 does not swell even when subjected to a higher temperature heat treatment, and a multilayer wiring board having a stronger adhesive strength of the insulating film layer 4 can be obtained.

In the case where the main conductor layer 7 is made of a copper layer, the uppermost main conductor layer 7 of the insulating film layer 4 is formed of a copper layer from the viewpoint of chip component mounting and environmental resistance. To form a nickel layer or a gold layer.

Thus, according to the multilayer wiring board of the present invention, the multilayer wiring board 2 is used for a hybrid integrated circuit device or a semiconductor element housing package for housing a semiconductor element, and is provided on the upper surface of the substrate 1. An electronic component such as a semiconductor element, a capacitor and a resistor is mounted and mounted thereon, and each electrode of the electronic component is electrically connected to the conductor layer 3 to be used as a semiconductor device or an electronic device.

The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention.

For example, in the above-described example, an example in which the LB film method is used as the method of forming the coupling agent layer 6 has been described. However, if the immersion method is used, the substrate on which the conductor layer 3 is formed is used. By dipping 1 in a coupling agent solution and further washing with a solvent, a coupling agent layer 6 having a desired thickness can be formed.

[0048]

As described above, according to the multilayer wiring board of the present invention, the coupling agent layer is formed on the upper surface of the main conductor layer to a thickness of 5 molecular layers or less. The arrangement is small, molecules of the main conductor layer and the coupling agent layer are efficiently bonded to each other to form a uniform and strong layer, and isolated coupling agent molecules are not generated. As a result, the heat resistance of the coupling agent layer is improved, the evaporation of the coupling agent layer in the heating step is eliminated, and the main conductor layer and the insulating adhesive layer are firmly bonded by the coupling agent layer.

Further, since the conductor layer is composed of a base conductor layer and a main conductor layer, the main conductor layer has good electric conductivity as a circuit wiring, and the base conductor layer has an adhesive strength with an insulating film layer. Can be adopted depending on the required function. Therefore, the adhesive strength between the insulating film layer and the main conductor layer can be strengthened, and it is not necessary to roughen the upper surface of the insulating film layer to have irregularities. Will not occur.

Thus, it is possible to obtain a multilayer wiring board which does not cause swelling of the insulating film layer due to the heat treatment, has strong adhesive strength of the insulating film layer, and is capable of high-density wiring.

Further, according to the multilayer wiring board of the present invention,
The base conductor layer is made of chromium or an alloy containing chromium as a main component, the main conductor layer is made of copper or an alloy containing copper as a main component, the insulating film layer is made of a polyimide resin, and the insulating adhesive layer is made of a polyimide siloxane resin. When the ring agent layer is formed of isopropyltri-N-aminoethylaminoethyl titanate, the isopropyltri-N-aminoethylaminoethyl titanate has good wettability with copper / polyimide resin / polyimide siloxane resin and easily bonds firmly, Further, since the heat resistance is high in the molecular structure, the adhesive strength between the respective layers is strengthened, and it is possible to cope with a higher temperature heat treatment. As a result, the heat resistance of the coupling agent layer is improved, the evaporation of the coupling agent layer between the insulating film layers is eliminated even at a higher temperature heat treatment, and the main conductor layer and the insulating adhesive layer are strengthened by the coupling agent layer. Adhered to.

Further, since chromium forms a chemical bond with the polyimide resin, the bonding strength is strong even if the upper surface of the insulating film layer is smooth. For this reason, unevenness on the upper surface of the insulating film layer becomes unnecessary, and even if a thin conductor layer is formed, disconnection does not occur, and the thin main conductor layer can be more firmly bonded to the insulating film layer.

Thus, a multilayer wiring board which does not cause swelling of the insulating film layer even by heat treatment at a higher temperature, has stronger adhesive strength between the insulating film layer and the conductor layer, and is capable of high-density wiring. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an embodiment of a multilayer wiring board of the present invention.

FIG. 2 is an enlarged sectional view of a main part showing a part of a conductor layer in the multilayer wiring board of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Multilayer wiring part 3 ... Conductor layer 4 ... Insulating film layer 5 ... Insulating adhesive layer 6 ... Coupling agent layer 7 ... ... Main conductor layer 8 ... Under conductor layer

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4E351 AA02 AA03 AA04 AA07 AA09 AA11 BB01 BB38 DD04 DD17 GG02 5E343 AA16 AA18 AA24 BB16 BB23 BB24 BB25 BB28 BB38 CC04 CC22 DD23 DD25 DD32 DD76 EE56 A10 CC05 CCA CC17 CC19 CC31 CC32 CC34 CC38 CC39 CC41 DD16 DD17 DD22 DD32 DD33 HH11

Claims (2)

[Claims] 1. A multilayer wiring board comprising a plurality of insulating film layers made of an organic resin and having a conductor layer formed on an upper surface thereof, the plurality of insulating film layers being adhered with an insulating adhesive layer and laminated on the substrate.
A multilayer wiring board, wherein the conductor layer comprises a base conductor layer and a main conductor layer, and a coupling agent layer having a thickness of 5 molecular layers or less is formed on an upper surface of the main conductor layer. 2. The insulating adhesive layer according to claim 1, wherein said base conductor layer is made of chromium or an alloy mainly containing chromium, said main conductor layer is made of copper or an alloy mainly containing copper, and said insulating film layer is made of a polyimide resin. 2. The multilayer wiring board according to claim 1, wherein the agent layer is formed of a polyimide siloxane resin, and the coupling agent layer is formed of isopropyl tri-N-aminoethylaminoethyl titanate.